What is the Immune System?

This is the first of a four part blog series that was taken from a research paper published by Dr. Mark Dedomenico, Director of The Hope Heart Research Institute. In this series Dr. Dedomenico discusses what makes up the immune system, how to evaluate your immune system, what weakens your immune system, and how to strengthen your immune system.

The overall health of individuals has been deteriorating over the last three to four decades due to excess body weight, chronic metabolic disorders, such as diabetes, and many damaging lifestyles such as lack of physical activity, increased stress, decreased sleep and smoking which all damage and weaken the immune system. The weaker a person’s immune system, the more severe symptoms they may experience if they contract a virus like COVID-19 or one of its mutations. Plus, since the beginning of the pandemic, many people have developed increased anxiety and stress about COVID-19 further impacting their immune system.

Before vaccinations and medications such as antibiotics, the only defense against pathogens like viruses, bacteria, and fungus was the body’s immune system. Most of the time, the immune system was able to destroy a pathogen. What is different today? Prior to 1930 when vaccinations and medications became available, we were more physically active and did not eat a diet high in carbohydrates, fats and ultra-processed, energy-dense, and nutrient poor foods and beverages. Most of the population was normal weighted without chronic hypertension, diabetes, and other disorders. Back then, immune systems were super strong and if someone contracted COVID-19, they likely would have had mild cold symptoms for a short duration.


The immune system is a complex network of cells and proteins that defends the body against infection and disease. The immune system keeps a record of every germ (microbe) it has ever defeated so it can recognize and destroy the microbe quickly if it enters the body again. A strong immune system, working correctly, helps to keep someone from getting sick, reduce severity of illness, and prevent future illness. However, when it’s been compromised by inflammatory disorders such as high cholesterol, high blood pressure, diabetes, stress, anxiety, depression, and especially excess body fat, the immune system is weakened and pathogens and viruses like COVID-19 can more easily cause someone to become sick or diseased.

Many cells work together to protect the body. For example, if someone cut themselves, the area around the cut, and the cut itself, becomes red and inflamed. This is called an inflammatory reaction. The immune system is attracted to the inflammatory reaction, which releases several chemicals that attract immune cells to the inflammation to heal the wound.

The cells keep coming as long as the inflammation is present. If several areas of the body are inflamed, these inflammations can use up most of the immune cells and weaken the immune system. Therefore, if a new virus enters the body through the nasal mucosa, the tissue that lines the nasal cavity, there are not enough immune cells left to destroy the virus. As a result of a weakened immune system, the virus begins duplicating to take over the body resulting in severe illness and/or death.

To continue reading What Weakens the Immune System click here. Other posts in this blog series include How to Evaluate your Immune System and How to Strengthen your Immune System. We have also added an Immune System Frequently Asked Questions you may view by clicking here.

Written by: Dr. Mark Dedomenico, Director of The Hope Heart Research Institute and CEO and Owner of PRO Club and PRO Medical.

Dr. Mark Dedomenico, a former cardiovascular surgeon, played a key role in developing the procedure known as Coronary Bypass Surgery along with Dr. Lester Sauvage. Working together as two of the initial founders of the Hope Heart Institute, they also created some of the most significant developments in heart surgery. These included the creation of artificial heart valves and Bionit arterial grafts used to replace damaged or atherosclerotic arteries. Dr. Dedomenico’s work has also taken him into the areas of genetics, nutrition, exercise physiology, and behavior modification.

In 1992, Dr. Dedomenico began a new research project devoted to the treatment of early stage metabolic disease to prevent individuals from later needing cardiovascular surgery or medications to control hypertension, high cholesterol and diabetes. The research led to the creation of the 20/20 LifeStyles program. In 2002, 20/20 LifeStyles was selected as a credentialed provider of Microsoft’s weight-management program.
Dr. Dedomenico’s research and work with 20/20 LifeStyles remains ongoing and prevalent. He has formulated successful long term treatment methods of obesity, hyperlipidemia, hypertension, diabetes, depression, fibromyalgia, binge eating disorders and arthritis. Additionally, Dr. Dedomenico is currently involved in a major osteoarthritis research project in conjunction with Colorado State University. He is devising new methods to control, prevent and stop the disorder.
In addition to his experience as a practicing surgeon, Dr. Dedomenico spent many years overseeing one of the country’s largest and most respected privately-held companies, Golden Grain Macaroni Company, the producer of many well-loved consumer products, including Rice-a-Roni, Mission and Golden Grain pasta, Ghirardelli chocolates, and Vernell candies.

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